training happens only once a week, on friday.
you can chage the regime as much as you like,the only thing that matters is the regime was set when training happens
after training you will see green arrows next to skils that poped
if you trained something and it didn't pop, don't worry, the skill was improved but not enough so you can see it
make sure you have quality trainer, and that you focus your training to young players by giving them minutes (at least 48) in the posisions you train
good luck